The invention is directed to a process for the production of thiazoline-(3) compounds by reaction of an oxo compound with a metal sulfide, ammonia, and an oxo compound which is substituted by halogen in a position adjacent to the oxo group. Thiazoline-(3) compounds serve as oxidation inhibitors for polyolefins. They are also starting materials for the production of sulfur containing amino acids such as cysteine and penicillamine.
It is known to produce 2,5,5-trialkyl substituted thiazoline-(3) compounds by reacting alkylidene vinyl amines with sulfur (Schade German Auslegeschrift No. 1,063,602), or by reaction of an aldehyde branched on the .alpha.-carbon atom with sulfur and ammonia (German Offenlegungsschrift No. 1,795,299 and related Asinger U.S. Pat. No. 3,700,683). It is also known that thiazoline-(3) compounds having alkyl substituents in the 2,4 and 5 positions are formed by reacting ketones which have at least one hydrogen atom in the .alpha.-position to the oxo group with sulfur and ammonia (Asinger, Angewandte Chemie, International Edition 6 (1967) 907-919, particularly page 908). This process in some cases only results in moderate yields. Besides, according to this process only certain thiazoline-(3) compounds can be recovered. Thiazolines which are not substituted in the 2- or 5- position or in 2-, 4- or 5-positions are not accessible by this process.
Besides, it is known to produce thiazoline-(3) in a given case substituted in the 2,4 and 5 positions by reaction of .alpha.-mercaptoaldehydes, .alpha.-mercaptoketones or S-acetylated .alpha.-mercaptoketones with oxo compounds and ammonia (Asinger, Angewandte Chemie, loc. cit., particularly pages 909 to 910). There are produced thiazoline-(3) compounds, in a given case substituted in the 2,4 and 5 positions from 2,2-dioxodisulfides, oxo compounds, ammonia and hydrogen sulfide (Asinger U.S. Pat. No. 3,004,981) or there are produced 2 and 5 position substituted thiazoline-(3) compounds by such process (Offermanns German OS No. 2,254,701 and related Offermanns U.S. Pat. No. 3,931,208). The disadvantage of this process is that it requires starting materials which are not readily accessible.
Finally, it is known to produce thiazolines-(3) which are substituted or unsubstituted at will in the 2-,4- and or 5-positions by reaction of an oxo compound with a metal sulfide, ammonia and an oxo compound which is substituted on the carbon atom adjacent to the oxo group by halogen, where preferably the oxo compound is present with the metal sulfide and to simultaneously add the ammonia and the oxo compound substituted by halogen (Ger. OS 2645731 and related Scherberich U.S. Pat. No. 4,153,606, e.g. column 4, lines 36-41). In this process there are indeed produced favorable yields but there are needed relatively long reaction times. The entire disclosure of Scherberich U.S. Pat. No. 4,153,606 is hereby incorporated by reference and relied upon.